The present invention relates to a pivotable mullion assembly for a double door. More particularly, the present invention relates to a pivotable mullion assembly controlled by a key cylinder lock mechanism.
Mullions are vertically oriented doorway inserts that allow use of single doors in double door frames. Conventionally, mullions are centered in a double doorway and attached with screws or bolts to fittings inset into the floor and the top of the door frame. Two strikes are provided on opposing sides of the mullion to accommodate latches of two single size doors that are respectively hinge mounted on opposite side of the door frame.
When unobstructed access through the double door is needed, conventional mullions must be unscrewed or unbolted from the inset fittings. This can be time consuming and difficult procedure, and normally requires two people. One person must hold the mullion while the other person unscrews or unbolts the mullion from the fittings. However, repeated removal and replacement of the mullion can also cause problems, with the fittings tending to become loose with time, or screw threads being stripped or damaged.
To overcome this problem, removable mullions that do not require unscrewing or unbolting have been disclosed. For example, U.S. Pat. No. 2,275,730 discloses a mullion capable of being seated in a floor bracket and swung forward to permit a latch bolt to snap into abutting relation with a tooth, holding the mullion in position against a top bracket. The mullion can be released by an actuating chain that retracts the latch bolt into a housing beneath the tooth, permitting inward tilting and complete removal of the mullion.
Movable mullion assemblies that remain attached to a doorway are also known in the prior art. For example, a pivoting mullion system is described in U.S. Pat. No. 1,258,638 to Tomkinson and Prescott. This mullion system includes a folding mullion that can be lifted out of the doorway using a hoisting chain. The mullion can be lifted straight upward, or alternatively rotated upward about a pivot attached to the top of the doorway.
However, mullion assemblies known in the prior art are disadvantageous for many applications because the mullion release system is not protected against damage or unauthorized removal by vandals. What is needed is an easily pivoted mullion assembly that can be snapped into an upright position to secure hinged doors, does not require multiple persons to remove or align, and is not pivotable or removable by unauthorized persons.
The present invention uses a key controlled lock mechanism to provide such a vandal resistant mullion assembly. A mullion assembly in accordance with the present invention includes a bottom fitting attached to a floor and a top fitting attached to the door frame above the bottom fitting. In preferred embodiments, the bottom fitting includes a pivot pin extending through the mullion cavity to hold the mullion in position, although other attachment mechanisms such as slip bolts, hinges, interlocking flanges, or other conventional pivoting mechanisms can also be employed.
The top fitting supports a bolt engagement assembly that can engage a bolt or other key controlled extendable element. A mullion, defining a mullion cavity therein, is positioned between the bottom fitting and the top fitting, and a lock assembly is positioned in the mullion cavity. The lock assembly includes a casing supporting a bolt and a key cylinder. Rotation of a key in the key cylinder causes alternate extension or retraction of the bolt to respectively engage with or disengage from the bolt engagement assembly of the top fitting. Typically, the bolt engagement assembly is a conventional strike dimensioned to accommodate the bolt and hold the mullion in a fixed position.
In certain embodiments, the bottom fitting of the mullion assembly can optionally include a lock mechanism, such as a screwlock extending between the bottom fitting and the mullion. This provides additional security, since only when the screwlock is disengaged from its connection between the bottom fitting and the mullion is pivoting motion of the mullion permitted.
Further features, objects, and advantages of the present invention will become more apparent upon consideration of the accompanying claims, drawings, and the following description of those drawings.